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Unit-II

Method Study

Introduction to Work Study

Frederick Winslow Taylor (1856-1915) and Frank B. Gilberth (1869-1924) are

originators of work study (Time & Motion study). Time and motion study were

developed separately. Taylor invented time study whereas Gilberth invented motion

study. Work study is a technique which deals with the problems:

As to how should a job be done/completed, and

How much time a job should take for completion.

Objective of work study is to determine the best method of performing each operation

and to eliminate wastage so that production increases with less human fatigue. The work

study is also used in determining the standard time that a qualified worker should take to

perform the operation when working at a normal pace.

Method Study (Motion Study)

Historical Background

In this field, pioneering work was done by Frank B. Gilberth. In 1885, at the age of 17,

was a junior apprentice bricklayer at Whidden and Co. He soon discovered that if proper

coordination between the mason and labor is maintained then the speed of bricklaying

increases many times. During 1910, lot of work was done by him with name of “motion

study”. In 1917, he suggested the adoption of “Motion Study”. Later on, the scope of

motion study was enlarged and it was named as “Method Study”.

Definitions

According to Frank B. Gilberth, motion study is “the science of eliminating wastefulness

as well as unnecessary, ill-directed and in-efficient motions”. Frank B. Gilberth was only

interested in motion economy by eliminating repetitive motions during the performance

of a job and determining the best and convenient method of performing a job under the

existing conditions so that a worker can consistently work for a longer time with

maximum comfort and safety.

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Method study is the systematic recording and critical examination of existing and

proposed ways of doing work as a means of developing and applying easier and more

effective methods and reducing costs.

Objectives of Method Study

Some important objectives of method study are:

i. The improvement of processes and procedures.

ii. To eliminate wastage of time and labor.

iii. Prevention of fatigue and breaking the monotony (dullness) of repetitive work.

iv. To find the best way of doing a job.

v. To improve the design of workplace layout.

vi. To train the individual worker in its practice as per standardized method.

vii. Reduction of waste and scrap, improvement in quality.

viii. Effective material handling.

ix. Greater job satisfaction, higher standards of safety and health.

x. Improvement in the flow of production and processes.

Need of Method Study

i. Method/motion study is a means of enhancing the production efficiency

(productivity) of the firm by elimination of waste and unnecessary operations.

ii. It is a technique to identify non-value adding operations by investigation of all the

factors affecting the job.

iii. It is the only accurate and systematic procedure oriented techniques to establish

time standards.

iv. It is going to contribute to the profit as the savings will start immediately and

continue throughout the life of the product.

v. It has got universal applications such as in:

a. Industries

b. Marketing, sales and distributions

c. Material handling

d. Design

e. Building and other constructions

f. Hospitals

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g. Transport etc.

Pre-requisites of Conducting a Method Study

The workers must be taken into confidence

They should not feel that they are kept in dark

Good human relationship

Good working conditions

Role of Work Study in Improving Productivity

Both the aspects of work study i.e. method study and work measurement tend to raise the

productive efficiency of the workers and hence, the productivity of an industry.

Work Study

Method Study Work Measurement

Higher Productivity

Method study increases productivity because it:

i. Cuts down the work content of the job by eliminating unnecessary and un-

useful/unproductive motions

ii. Develops the best method of doing a job which imparts least fatigue to the

operators

iii. Results more effective use of machinery, man-power and material.

iv. Improves design of work place layout

v. Improves the better working conditions and relations

Work measurement increases productivity because it:

i. Reduces ineffective time

ii. Suggest rest, pauses and other allowances which results the operators in a position

to maintain their productive efficiency

iii. Provide a sound basis for giving incentives to the workers to produce more

iv. Calculates the correct man-power required for doing a job, and

Results in more effective use

of material, manpower, plant

and equipment

Making possible improved planning

and control. Making as a basis for

sound incentive schemes

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v. Aids in accurate production planning

Hence, if correct and systematic work study is done in any organization than higher

productivity is natural.

Procedure of conducting Method Study

Method study procedure consists of the following steps (See Figure 1):

1. Select

2. Record

3. Critically examine

4. Develop the best method

5. Define

6. Install

7. Maintain

Recording Techniques

The recording techniques are designed to simplify and standardize the recording work.

The purpose of recording can be summarized as follows:

i. To enable the process to be clearly understood

ii. To present the existing facts for analysis

iii. To submit the proposals to the management in a form which can be easily

understood

iv. To guide supervisors and operators regarding detailed operating instructions

In order to make presentation of facts clearly, without any difficulty and to enable to

grasp them quickly and clearly, it is better to use symbols instead of written description.

The following are the basic types of diagrammatic aids used for recording and

communicating a work method. These are:

i. Process Charts

ii. Diagrams

iii. Templates and Models

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Results

Recor

Method Study

Select the job to be

studied

Record facts relating to

existing/proposed methods

Examine all relevant facts

critically but impartially

Diagrams Charts Models

Place Person Sequence Mean

s Purpose

Develop alternatives to the existing method

Select the most economical method and define it

(New method)

Install the new method

Plan-arrange-implement

Maintain the new method, verify its

implementation at regular intervals

To achieve improved factory and workplace layout,

improved design of equipment, better working conditions,

reduction of fatigue, effective use of material, plant,

equipment and man-power

HIGHER

PRODUCTIVITY

Figure 1: Procedure in Method Study

Factors

Economic Considerations (time pd.,

job nature and use)

Technical Considerations (skill, f, d,

N cutting tool, material)

Human considerations

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Process Charts

Definition

A chart representing a process may be called a process chart and is used for recording a

process in a compact manner, as a means of better understanding it and improving it. The

chart represents graphically or diagrammatically the sequence of operations or events that

occur during the performance of a task or a process. The chart uses various sets of

symbols and aids for better understanding and examining the process.

Process Chart Types

Process charts are of the following types:

i. Outline Process Chart

ii. Flow Process Chart

iii. Two-hand Process Chart

iv. Multiple Activity Chart

Process Chart Symbols

In 1947 American Society of Mechanical Engineers (ASME) established five (05)

standard symbols which are universally accepted to prepare charts. The various symbols

used in process charts are as follows (Table 1):

Table 1: Description of Process Chart Symbols

S.No. Event/Activity Symbol Operation/Description

1. Operation Operation represents an action i.e.

change in the location or condition

of a product. Example: cutting of a

bar on a power hacksaw; turning;

filling; joining; assembling etc.

2. Storage

It represents a stage when a finished

good or raw material awaits an

action. Example: Nut is to be

assembled with bolt, milling cutter

lying in tool store; finished goods

ready for sale etc.

3. Inspection

It is an act of checking for

correctness of the quantity or quality

of the item. Example: checking the

hardness of a MS piece; checking

the weight of a packed tin etc.

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4. Transport

It indicated the movement of an

item from one location to another.

Example: Oil flowing through a

penstock; MS bar being sent from

store to M/c shop; gear blank from

lathe to milling M/c etc.

5. Delay or Temporary

Storage

Delay occurs when something stops

the process and a product waits for

the next event. Example: Power

failure; traffic jam; machine

breakdown etc.

6. Operation-cum-

Transportation

Example: Article are being painted

as they are transported by belt

conveyor.

7. Inspection-cum-

Operation

Example: Powder milk tin is being

weighed (inspection) as it is filled.

Both the events occur

simultaneously.

Flow Process Chart

A flow process chart is detailed version of outline process chart and it records all the

events. It is defined as a graphical representation of all events, operations, inspections,

transportations, delays and storages occurring during a process by means of process

symbols. There are three types of flow process charts, namely:

i. Man-type flow process chart

ii. Material-type flow process chart

iii. Equipment-type flow process chart

Man-type-records activity of worker/operator (See Figure 2(a))

Material-type-records what happens to the material (See Figure 2(b))

Equipment-type-records the manner in which the equipment is used (See Figure 2(c))

Exercise 1: Task: Riveting the two MS plates by means of rivets (Butt Joint).

Figure 2(a): Man-type Flow Process Chart

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Summary

Events No. Time Distance

(in meters)

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1

1

2 30

1

Total 12 30m

Exercise 2: Task: Making the casting ready for machining.

Chart begins- Casting lying in foundry

Chart ends- Casting ready for machining

Activity Operations Distance

moved

(in meters)

Time

(in minutes)

Remarks

(if any)

Casting lying in the

store

Moved to gas cutting

M/c

10 3 By trolley

Wait cutting M/c

being set

5

Risers cut/out

20

Wait for trolley

10

Moved to inspection

department

6 2 By trolley

Inspection before

M/cing

15

Moved to M/c shop

10 3 By trolley

Figure 2(b): Flow Process Chart of Material type

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Summary

Events Number Time Distance

1 20

1

2 15

3 8 26

1

Total 8

Exercise 3: Task: Flow process chart of equipment type- Watering the garden using hose

pipe.

Equipment: Hose-pipe

Job: Watering the garden

Chart begins: Hose lying in the cupboard Summary:

Chart ends: Hose lying in the cupboard

Pipe lying in cupboard

Lifted

Removed from tap

To tap Fixed to tap Used for watering

3m To cupboard

1m

Re-placed in cupboard

1

1

1 2 3 4

2

5 2 Lying in

cupboard

Figure 2(c): Flow Process Chart of Equipment type

Events No. Time

(in mints.)

Distance

(in m)

5 - -

2 - -

2 - 4

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Exercises:

Writing a letter using a shorthand typist.

Polishing the specimen and looking for the microstructure.

Issuing of book (any type) from book bank.

Draw a flow process chart (man type) performing an operation on UTS M/c.

Two-hand Process Chart

A two hand process chart is a process chart in which the activities of a worker’s left hand

and right hand along with limbs are recorded while he is performing an operation at any

work station. The activities of two hands and limbs can be analyzed by providing a time

scale on the chart and repetitive, unnecessary, uneconomical activities can be neglected.

Here meaning of symbols is slightly changed as:

-----When hand is idle not performing any activity,

----- Hold---Hand holds the object so that other hand to some activities on that object,

---- Movement of hand here & their, and

------- Operation—grasps, release, assemble etc.

This chart is generally used for analysis of short duration and assembly work.

Exercise 1: Assembly of two washers and nut to bolt (See Figure 3(a)).

Chart begins: Hand empty, material in boxes.

Chart ends: Completed assembly placed in other box.

Method: Present/Proposed

Left Hand

Description

Symbol

(LH)

Time

(Minutes)

Symbol

(RH)

Right Hand

Description

To bolt 0.5m 0.5m To first washer

Pick up bolt Pick up washer

To position 0.5m 0.5m To position

Hold Assemble to bolt

Hold 0.5m To second washer

Hold Pick up washer

Hold 0.5m To position

Hold Assemble to bolt

Hold 0.5m To nut

Hold Pick up nut

Hold 0.5m To position

To box 0.5m Assemble to bolt

Put in the box Idle

Figure 3(a): Left Hand and Right Hand Chart

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Summary:

Symbol Number Time Distance Symbol Number Time Distance

2 6

3 1.5m 6 3.0m

- 1

9 -

Exercise 2: Assembly of nut and bolt (See Figure 3(b)).

LH Symbol

RH LH RH

Pick up bolt Idle

Hold Pick up nut

Hold To left hand

Hold Assemble (screw up)

To box Idle

Figure 3(b): Left Hand and Right Hand Chart

Summary:

LH Nos. RH Nos.

1 2

3 -

1 1

- 2

Exercises:

1. Draw a left hand and right hand chart for signing a letter and give detailed

summary.

2. Draw a LH and RH chart for opening a bottle of coke.

3. Draw a RH and LH chart for changing the battery of wall cloak.

Multi-activity Chart

It is a chart where a number of workers work in a group or an individual operator handles

two or more machines or equipments, their activities are recorded on a common time

scale and thus, shows inter-relations between them.

They may be of the following type:

i. Man-machine chart---one man handling one job or one machine.

ii. Man-multi machine chart---one man handling number of machines.

iii. Multi-man chart---a group is doing one job.

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iv. Multi-man-machine chart---a number of persons working on a computer system.

Exercise 1: An operator working on two machines (See Figure 4(a)).

Time

(in minutes)

Man

(Operator)

Machine-1 Machine-2

10 Setting M/c-1

M/c being set Idle

5 Setting M/c-2

M/c-1 working

M/c is being set

10 Idle

M/c-2 working

5 Setting M/c-2 M/c-2 being set

5 Idle M/c-2 working

5 Setting M/c-1 M/c-1 being set

10 Setting M/c-2

M/c-1 working

M/c-2 being set

5 Idle Working

Figure 4(a): Multi Activity Chart of one Man Working on Two Machine

Summary:

Working Time

(minutes)

Idle Time

(minutes)

Operator 35 20

Machine-1 40 Nil

Machine-2 25 10

Exercise 2: Job-Making a slot on the casting (See Figure 4(b)).

Time

(in minutes)

Man Machine Time

(in minutes)

0.2

Removes finished casting

cleans with compressed air

Idle 0.2

0.4

Cleans machine with

compressed air

Idle 0.4

0.6

Locate a new casting in a

fixture, start machine and

auto feed

Idle 0.6

0.8

Break sharp edges with file,

clean with compressed air

Cutting slot 0.8

1.0 Gauges depth of slot on

surface plate

Cutting slot 1.0

1.2 Places casting in a box, pick

up new casting

Idle 1.2

1.4 Idle Cutting slot 1.4

Figure 4(b): Man-machine Chart

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Summary:

Cycle Time= 1.4 minutes M/c Working Time= 0.6 minutes

Man’s Working Time= 1.2 minutes Machine Idle Time= 0.8 minutes

Man’s Idle Time= 0.2 minutes

Utilization: Man= %851004.1

2.1

Machine Utilization= %421004.1

6.0

Man-Machine Chart

It has two parts, on one side the action of the operator is recorded and on the other side

the action of the machine is recorded with reference to a common time scale.

Example: A man working on three machines at a time.

Time

(in seconds)

Man Machine-1 Machine-2 Machine-3

Unload M/c-3

Running

Running

Stopped

Load & start M/c-3

Move to M/c-1

Running Wait

Unload M/c-1 Stopped

Wait

Assuming that the machines are running state

Figure 5: Man-machine chart

Exercises:

i. Construct a multi-activity chart of two men working on two drilling machines and

drilling a hole (with summary).

ii. Construct a man-machine chart of a man working on a computer system and is

typing an application and taking out the print.

iii. Draw a man-machine chart if one man is operating one drilling machine and other

on cutting machine.

iv. Draw a man-machine chart of your choice using two men and three machines.

Also, calculate each machine utilization and men utilization percentages.

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Flow Diagram

It is a drawing or a diagram which is drawn to scale and marks the path followed by men

and materials. Flow diagram is used to supplement the flow process chart. It shows the

relative position of productive machinery, storage area, jigs, fixtures, etc. shown by

joining the symbols with straight lines. Flow diagram may minimize the number of

movements or repetitive movements which results in a lot of saving both in cost as well

as efforts required to do a job.

Figure 6: Flow Diagram of Flow of Material on a Shop Floor

Exercises:

i. Construct a flow diagram of a notice being circulated in University Polytechnic

regarding minimum percentage of attendance for appearing in examination

consisting of four sections.

ii. Construct a flow diagram of issuing a book, reading in the reading room and

returning the same at Maulana Azad Library.

iii. Construct a flow diagram of University Polytechnic Workshop if a raw material is

issued from Workshop store is processed through various shops namely fitting,

welding, foundry, machine shops, and finally in inspection unit to the market.

B 2 A

3

1

4

A, B, C & D----Shops

Store 5

Out

2 1

1

C

1

D 1

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Principles of Motion Economy

Principles Governing Motion Study

Set of rules were designed by Gilberth in order to develop better method. They are:

Both hands should move simultaneously. This reduces fatigue.

Both hands should complete their movements at the same time i.e. they should

start and finish their motions at the same time.

Both hands should not be idle at the same time unless in a rest period.

Between two movements there should be some time gap. The time gap is called

elapsed time (pass).

Motion of both the hands should be symmetrical and in opposite directions and

should be made simultaneously.

Hesitation in any movement observed at any time should be analyzed.

The shortest time demonstrated by any worker should be marked and efforts

should be made to attain it.

The number of motions required to do a particular work should be clearly

specified.

Variations in time for any movement should be avoided and causes recorded.

All motions should be easy, natural and should reduce fatigue.

Introduction to Therbligs

To facilitate the analysis of motion, Gilberth developed a set of smaller hand motions

some of which could be combined to give a complete motion. The smaller motions he

termed as “Therbligs” (reverse spelling of his name). They are 18 in numbers. For the

purpose of recording the motions, he split up different motions of a process into 18

fundamental hand motions. Every therblig is represented by a symbol, a definite color

and with a word or two to record the same (See Table 2).

A chart which uses or employs Therbligs is referred as “micro-motion study

chart” while a chart which uses symbols like etc. which are macroscopic

in nature is referred as process chart. SIMO chart is a microscopic chart. A single

operation may consist of many Therbligs.

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For example:

Macroscopic motion Microscopic Motion

(Therbligs)

Operation of picking away a screw

driver

Reach hand for screw driver

(Transport empty)

Grasp the same (Grasp)

Take away the screw driver (Transport

loaded)

Table 2: List of Therbligs

S. No. Name Abbreviation Symbol

1. Search S

2. Hold H

3. Select SE → 4. Grasp G

5. Release Load RL

6. Transport Loaded TL

7. Transport Empty TE

8. Position P و 9. Preposition PP

10. Assemble A # 11. Dissemble DA ╫

12. Use U U

13. Inspect I

14. Avoidable Delay AD

15. Unavoidable Delay UD

16. Rest R

17. Plan PN

18. Find F

Micro-motion Study

Micro-motion study means the study of micro (small) motions know as Therbligs. Each

human activity is divided or split into small movements. The purpose of such study is to

find for an operator one best pattern of movement which involves less efforts, time, and

fatigue to accomplish a task. This study is best suited for those operations which are short

in cycle and are repeated thousands of time (such as packing of sweets into boxes, food

canes into cartons, launching of space craft, missiles, modern cricket, athletics etc.).

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Micro-motion study involves taking motion pictures of an activity while being

performed by the operator with a timing device kept in the field of view and than film is

studied on the projector frame by frame.

Following equipments are required for this study:

1. Movie camera.

2. 16mm film for recording.

3. Micro-chronometer or Wink counter (1 Wink=1/2000 of a minute).

4. Motion picture projector with screen.

Exercise: What are the advantages and applications of micro-motion study? Give the

step-wise procedure of micro-motion study.

Exercise: Motion used in filling ink in a fountain pen.

S.No. Name of Motion Symbol/

Abbreviation

Description of Motion

1. Search S Look for the pen

2. Transport Empty TE Approach/reach to the pen

3. Grasp G Pick up the pen with fingers

4. Transport Loaded TL Move the pen to ink-pot (which is

open)

5. Position P Set the pen in position

6. Use U Operate plunger to fill the ink

7. Transport Loaded TL Move the pen to the stand

8. Release Load RL Put the pen on the stand

9. Transport Empty TE Return the hand in original position

Exercise: Motions used in signing a letter

S.No. Name of Motion Symbol/

Abbreviation

Description of Motion

1. Transport empty TE Reach for pen

2. Grasp G Take hold of pen

3. Transport loaded TL Carry pen to the paper

4. Position P Position pen on paper for writing

5. Use U Sign letter

6. Transport loaded TL Return pen to the holder

7. Pre-position PP Position pen in holder

8. Release load RL Let go of pen

9. Transport empty TE Move hand back to letter

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Exercise: Study the motions used in following operations using therbligs:

i. Cleaning your teeth with tooth brush.

ii. Packing three types of sweets in a box.

iii. Punching a hole in a lock body.

iv. Planting a flower plant in the pot.

Note: Use both the hands in performing the above tasks.

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